=Operation.= _First step._ The position for the new external canthus is determined by holding the lids together at the outer canthus, and is marked on the upper and lower lids. From these points incisions are carried outwards to the external canthus along the intermarginal line in the top and bottom lids. These incisions are deepened to about 5 millimetres. _Second step._ From the inner end of the incision in the lower lid a vertical one is made downwards for about 5 millimetres, and is then carried out to the external canthus. The tissue thus marked out, bearing the lashes, is then removed. _Third step._ A corresponding, slightly larger, area is similarly removed from the under or conjunctival surface of the upper lid (Fig. 139). [Illustration: FIG. 139. CANTHORRHAPHY.] _Fourth step._ These two areas are brought into apposition by means of a strong suture passed through their centre. The suture should have a needle at either end, and these should be passed from the conjunctival surface and brought out through the middle of the raw area in the lower lid, about 2 millimetres apart, and then through the middle of the raw area in the upper lid and out through the skin. The suture is tied so that the two raw areas are brought into accurate apposition. The margins of the wound may then be brought together by sutures if necessary. The main suture should be left in for at least ten days. TARSORRHAPHY =Indications.= (i) Complete union of the eyelids may be required when an eye has been removed and for some reason an artificial one cannot be worn. (ii) Partial union is effected in cases of paralysis of the first division of the fifth nerve when corneal ulceration threatens. A similar union is also useful in keeping the lower lid in position during the process of cicatrization in many of the operations for ectropion described below. The adhesions produced can be subsequently divided when contraction has ceased. =Instruments.= Knife, forceps, scissors, spatula. =Operation.= _Complete._ As narrow a strip of tissue as possible is removed from the lid borders behind the eyelashes. This is best performed by everting the upper lid and shaving off the posterior margin with a sharp knife; the lower lid is then treated similarly. The raw areas are brought into apposition with fine sutures. _Partial._ When only a temporary adhesion is required, as after ectropion operations, it is sufficient to make raw corresponding areas of about 2 millimetres on the posterior margins of the top and bottom lids on either side of the central position of the cornea and unite them with sutures, which may be removed about the end of the first week. PTOSIS OPERATIONS